Hierarchical hollow microsphere and flower-like indium oxide: Controllable synthesis and application as H2S cataluminescence sensing materials

In the present work, In2O3 hierarchical hollow microsphere and flower-like microstructure were achieved controllably by a hydrothermal process in the sodium dodecyl sulfate (SDS)-N,N-dimethyl-formamide (DMF) system. XRD, SEM, HRTEM and N2 adsorption measurements were used to characterize the as-prepared indium oxide materials and the possible mechanism for the microstructures formation was briefly discussed. The cataluminescence gas sensor based on the as-prepared In2O3 was utilized to detect H2S concentrations in flowing air. Comparative gas sensing results revealed that the sensor based on hierarchical hollow microsphere exhibited much higher sensing sensitivity in detecting H2S gas than the sensor based on flower-like microstructure. The present gas sensor had a fast response time of 5 s and a recovery time of less than 25 s, furthermore, the cataluminescence intensity vs. H2S concentration was linear in range of 2–20 μg mL−1 with a detection limit of 0.5 μg mL−1. The present highly sensitive, fast-responding, and low-cost In2O3-based gas sensor for H2S would have many practical applications.